1. Field of the Invention
This invention relates to devices for measuring the water drainage characteristics of selected non-skid surfaces, including open-grated surfaces and more particularly, to a self-contained symmetrical outflow meter for resting on the surface and timing the water drainage through the texture voids. In a preferred embodiment the outflow meter is characterized by an elongated, cylindrical, vertically-oriented water discharge tube for containing water. The water discharge tube is mounted in a circular base having a pair of handle supports which extend upwardly from the base on respective sides of the water discharge tube, in substantially diametrically-spaced relationship with respect to each other. A handle spans the upper end portions of the handle supports and a circular funnel is mounted between the handle supports, beneath the handle and above the water discharge tube. A spring-loaded plunger is slidably suspended from the funnel, into the water discharge tube for selectively sealing a water discharge opening provided in the base. Upper and lower adaptors of different lengths, wired to a timer typically provided on a timer support spanning the handle supports, are suspended from the funnel inside the water discharge tube, and upper and lower switch floats are vertically displaceably mounted on the respective upper and lower adaptors. In application, the base is placed on the pavement or other surface to be tested and the plunger is operated to seal the water discharge opening. Water is then poured into the water discharge tube through the funnel, to a level which exceeds the level of the upper switch float. When the water is at this level, both the upper and lower switch floats are in the raised or top position on the respective adaptors and this prevents the timer from operating. The timer is reset to xe2x80x9czeroxe2x80x9d and the plunger is released to unseal the discharge opening, thus allowing the water to flow from the water discharge tube through the discharge opening onto the surface to a sealing ring on the bottom surface of the base to search for texture voids in the test surface. As water flows from the water discharge tube through the discharge opening onto the surface and leaks through the texture voids under pressure of gravity, the water level in the water discharge tube falls below the upper switch float, which is displaced downwardly by gravity on the upper adaptor, while the lower switch float remains in the upper position on the lower adaptor. This causes the electronic timer to begin counting. As the water level continues to fall below the level of the lower switch float, the lower switch float is likewise downwardly displaced by gravity on the lower adaptor, and this causes the timer to stop counting. The time required for the water level in the tube to fall from the level of the upper switch float to the level of the lower switch float is indicated on the timer and indicates the rate of water drainage of the pavement surface upon which the outflow meter is placed.
2. Description of the Prior Art
A typical conventional outflow meter is characterized by a vertical water discharge tube having a base and a base seal for resting on a surface such as pavement, a cap mounted on the tube top and a plunger suspended from the cap for reversibly sealing a water discharge opening provided in the base. A pair of brass probes is typically suspended from the cap into the tube at different levels. Each probe is provided with a jack included on the cap, and a pair of cables, wired to an electronic timer and circuit board, are inserted in the jack. The base seal of the outflow meter is placed on the pavement or other surface and the tube is filled with water to a level exceeding the bottom end of the top brass probe, immersion of which prevents timer activation. After the discharge opening is unsealed and the water level in the tube drops below the level of the upper brass probe, the timer is activated. As the water level drops below the lower probe, the timer is stopped and the time required for the water level to drop from the upper probe to the lower probe, displayed on the timer, reveals the drainage characteristics of the pavement surface. However, this type of outflow meter is cumbersome to use, since care must be exercised to prevent the water from the tube from contacting the cable pins and jacks on the tube top, in order to prevent an electrical short and accompanying erroneous readings on the timer. The new and improved, self-contained outflow meter of this invention utilizes a pair of upper and lower adaptors having switch floats which are provided on the adaptors, respectively, in place of the brass probes of the conventional outflow meter. Because the upper and lower adaptors of the outflow meter are wired directly to the electronic timer through a sealed and waterproof corridor, the need for a cable trailing from the adaptors to the electronic timer and circuit board is eliminated, also eliminating the need for exercising special care in preventing water in the tube from contacting the cable pins and jacks. Another outflow meter for measuring surface drainage characteristics of pavement is detailed in U.S. Pat. No. 4,070,903, dated Jan. 31, 1978, to Geoffrey Lees, et al, entitled xe2x80x9cOutflow Meter for Measuring Surface Drainage Characteristicsxe2x80x9d. The outflow meter is characterized by a disk having a surface-engaging face which is disposed in contact with the surface being measured, an orifice extending through the disk and terminating at the surface-engaging face, a mechanism for pressing the disk into engagement with the surface under a predetermined load and a mechanism for supplying a predetermined volume of fluid through the orifice to the surface-engaging face. My U.S. Pat. No. 5,780,720, dated Jul. 14, 1998, describes an xe2x80x9cOutflow Meterxe2x80x9d for resting on pavement and measuring the rate of water drainage from the pavement. The outflow meter includes a vertical tube for containing water and having a bottom water discharge end sealed by a rubber sealing ring. A spring-loaded plunger is suspended from a cap mounted on the upper end of the tube for selectively sealing a water discharge opening provided in the base. Upper and lower float switches are suspended from the cap into the tube and include upper and lower switch floats, respectively, which are vertically displaceably mounted. A timer is provided on the cap and is wired to the float switches. The base is placed on the surface with the plunger sealing the water discharge opening and the water is poured into the tube. As the water level exceeds the respective levels of the switch floats, the floats are displaced upwardly. The plunger is then released, allowing the water to flow from the tube through the discharge opening onto the surface and under the sealing ring on the base. The floats are sequentially displaced by gravity and the timer records the elapsed time of water flow between the float switches and from the tube, thus indicating the rate of water drainage from the surface.
One of the problems associated with the outflow meter described in my U.S. Pat. No. 5,780,720, is the relative instability of the outflow meter on a pavement surface due to the unequal weight distribution and lack of symmetry inherent in the design of the outflow meter, insofar as the handle and timer of the meter are both mounted on the same side of the meter. Moreover, the funnel of the meter, used for pouring the water into the meter, is too small, thus rendering it difficult to pour water into the water discharge tube, and water can be poured into the tube from only one side of the meter. Furthermore, the tapered rubber plunger head of the meter has a tendency to inadvertently slip out of the water discharge opening before or during pouring of water into the water discharge tube, and this causes premature release of water from the water discharge opening at the bottom of the tube. In contrast, the handle and timer of my new and improved outflow meter are mounted in the center of the meter, at the top thereof such that the center of gravity of the meter is substantially at the center, rather than oft center, of the meter, thus rendering the meter more stable on pavement surfaces. The circular funnel of the outflow meter of this invention extends 360 degrees around the meter, such that water can be poured into the water discharge tube from either side of the meter. Finally, the plunger head of the outflow meter of this invention is fitted with a TEFLON (trademark)-coated neoprene ring which snugly fits into the water discharge opening of the meter, thus substantially preventing inadvertent slipping of the plunger head from the water discharge opening.
An object of this invention is to provide a new and improved, self-contained and compact outflow meter for measuring the water drainage rate on a pavement or other surface having a given texture.
Another object of this invention is to provided a new and improved outflow meter for measuring the water drainage characteristics of pavement, which outflow meter is characterized by portability, reliability, low maintenance, easy use and stability on a pavement surface.
Still another object of this invention is to provide a new and improved outflow meter for measuring surface drainage characteristics, which outflow meter is characterized by a circular base; a sealing ring provided on the bottom surface of the base for resting on a pavement or other surface; a pair of handle supports extending upwardly from the base, in substantially diametrically-spaced relationship to each other; a timer support spanning the upper ends of the handle supports; a handle spanning the handle supports beneath the timer support; a circular funnel mounted between the handle supports, beneath the handle; an elongated, vertical water discharge tube for momentarily holding a selected volume of water, mounted beneath the funnel, wherein water can be poured through the funnel and into the water discharge tube from either side of the handle supports of the outflow meter; a spring-loaded plunger for selectively sealing a discharge opening provided in the base, which plunger is fitted with a typically TEFLON (trademark)-coated neoprene ring and is substantially hindered from inadvertently slipping out of a discharge opening having minimal taper; and a pair of adaptors extending downwardly from the funnel into the water discharge tube at different levels and wired to the timer, one of which adaptors terminates near the top and the other near the bottom of the water discharge tube. A switch float is mounted on each adaptor and water is added to the water discharge tube until the water level in the tube is located above the level of both switch floats. By operation of the plunger, water flows from the water discharge tube through the discharge opening onto the supporting surface and when the water level falls below the upper switch float, operation of the timer is initiated. When the water level falls below the lower switch float, this action stops the timer. The period of time required for the water level in the water discharge tube to fall from the lowest level of the upper switch float to the lowest level of the lower switch float indicates the drainage characteristic of the surface.
These and other objects of the invention are provided in a new and improved, symmetrical outflow meter characterized by a transparent water containment and discharge tube which is vertically mounted in a circular base having a pair of handle supports extending upwardly from the base on respective sides of the tube, in substantially diametrically-spaced relationship to each other; a timer support which spans the upper ends of the handle supports; a handle which spans the handle supports beneath the timer support; and a funnel mounted between the handle supports above the water discharge tube and beneath the handle. An electronic timer and circuit are provided typically on the timer support and a spring-loaded plunger, mounted on the funnel and extending downwardly into the water discharge tube and fitted with a typically TEFLON (trademark)-coated neoprene ring, operates to selectively and reversibly seal a discharge opening in the base by hand pressure. In a most preferred embodiment, an upper adaptor having a vertically-displaceable switch float mounted thereon, extends downwardly into the interior of the water discharge tube and terminates near the top of the tube and a lower adaptor extends downwardly into the tube to a point near the bottom of the tube and includes a similar switch float mounted thereon. Both adaptors are wired to the timer. As water is poured through the funnel into the water discharge tube while the plunger is in the sealing position in the base against the spring bias and the water level rises to the level of the upper float, displacement of the floats upwardly on the adaptors, respectively, prevents operation of the electronic timer. Since the outflow meter has been placed with the bottom sealing ring on the surface to be measured, release of the plunger from the discharge opening in the base allows water to drain from the water discharge tube onto the surface. As the water level drops below the level of the upper float, downward movement of the upper float by gravity activates the timer and as the water level drops below the level of the lower float, downward movement of the lower float by gravity on the adaptor terminates operation of the timer. The time required for the water level to drop in the water discharge tube from the level of the upper switch float to the level of the lower switch float is proportional to the drainage characteristics of the surface upon which the outflow meter is placed.